Which torque refers to the torque a motor produces when the rotor is stationary and full power is applied?

Locked-rotor torque refers to the torque produced by a motor when the rotor is not rotating, and full power is applied. This condition occurs when the motor is first energized, and the rotor is stationary due to mechanical constraints or high inertia. At this moment, the motor is drawing the highest amount of current, which leads to the generation of significant torque necessary to overcome the inertia and initiate motion.

Understanding this concept is crucial because it indicates the capability of a motor to start under load conditions. The locked-rotor torque is a key parameter in motor selection and design, particularly when dealing with applications where high starting torque is essential to move heavy loads. Each motor has a specified locked-rotor torque rating that signals how much torque it can produce under these conditions without risking damage or excessive current draw.

In contrast, pull-up torque relates to the motor's ability to increase from the starting point to a point just before it reaches full-load speed. Full-load torque is the torque necessary to keep the motor running at its rated load at rated speed, and breakdown torque refers to the maximum torque the motor can produce before it begins to stall or lose its ability to keep accelerating.